Results 81 to 90 of about 29,640 (237)

Early Cambrian U-Pb zircon age and Hf-isotope data from the Guasayán pluton, Sierras Pampeanas, Argentina: implications for the northwestern boundary of the Pampean arc [PDF]

, 2016
An Early Cambrian pluton, known as the Guasayán pluton, has been identified in the central area of Sierra de Guasayán, northwestern Argentina. A U?Pb zircon Concordia age of 533 ± 4 Ma was obtained by LA-MC-ICP-MS and represents the first report of ...
Alasino, Pablo Horacio, Baldo, Edgardo Gaspar Agustín, Basei, Miguel A. S., da Costa Campos Neto, Mario, Dahlquist, Juan Andrés, Rapela, Carlos Washington, Uran, Gimena Mariel, Verdecchia, Sebastián Osvaldo, Zandomeni, Priscila Soledad   +8 more
core   +2 more sources

Late Holocene moisture variability in Arctic Alaska from chitin δ18O

Boreas, EarlyView.
Amplified warming in the Arctic has resulted in reduced sea‐ice extent, which can impact regional climate dynamics. Elucidating past moisture variability in response to changing temperatures and sea‐ice conditions can offer insight into how anthropogenic climate change may impact Arctic areas such as the Alaskan North Slope in the future. We contribute
Briana A. Edgerton, Melissa L. Chipman
wiley   +1 more source

U‐Pb Geochronology of Paleosol Carbonate Cements by LA‐ICP‐MS: A Proof of Concept and Strategy for Dating the Terrestrial Record

Geochemistry, Geophysics, Geosystems
This study investigates the potential of laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) U‐Pb dating for carbonate nodules in the Late Triassic Ischigualasto Formation of northwestern Argentina.
L. E. Aguirre Palafox, A. Möller, N. M. McLean, G. A. Ludvigson, C. E. Colombi, I. P. Montañez   +5 more
doaj   +1 more source

Jadeite in Continental Subduction: Its Preservation, Breakdown and Pseudomorphic Replacement in Erzgebirge UHP Gneisses

Journal of Metamorphic Geology, EarlyView.
ABSTRACT The absence of jadeite in regions where subduction of continental crust has been documented by other high‐pressure (HP) or ultrahigh‐pressure (UHP) minerals is striking. This study presents only the second discovery of jadeite in the crystalline rocks of the Erzgebirge, a region known for its occurrences of microdiamond, coesite and omphacite ...
Ondrej Lexa, Martin Racek, Petr Jeřábek, Benjamin Paddon   +3 more
wiley   +1 more source

Impact and Correction of Analytical Positioning on Accuracy of Zircon U-Pb Dating by SIMS

Frontiers in Chemistry, 2020
Secondary ion mass spectrometry (SIMS) is one of the most important analytical tools for geochronology, especially for zircon U-Pb dating. Due to its advantages in spatial resolution and analytical precision, SIMS is the preferred option for multi-spot ...
Yu Liu, Yu Liu, Qiu-Li Li, Qiu-Li Li, Qiu-Li Li, Xiao-Xiao Ling, Xiao-Xiao Ling, Guo-Qiang Tang, Guo-Qiang Tang, Jiao Li, Jiao Li, Xian-Hua Li, Xian-Hua Li, Xian-Hua Li   +13 more
doaj   +1 more source

Variable Sr Diffusion and Implications for Rb–Sr Biotite Geochronology

Journal of Metamorphic Geology, EarlyView.
ABSTRACT The rubidium–strontium (Rb–Sr) system has a long pedigree as a geochronological tool that relies on the application of an isochron approach. In particular, biotite contains strongly radiogenic Rb–Sr isotopes, and thus can yield meaningful crystallisation or cooling ages via this approach. However, the response of the Rb–Sr system in biotite to
Riley Rohrer, Christopher L. Kirkland, Hugo Olierook, Tim Johnson, Katy Evans   +4 more
wiley   +1 more source

Extensional faulting on Tinos island, Aegean sea, Greece: How many detachments? [PDF]

, 2007
Zircon and apatite fission track (ZFT and AFT) and (U-Th)/He, 40Ar/39Ar hornblende, and U-Pb zircon ages from the granites of Tinos Island in the Aegean Sea, Greece, suggest, together with published ZFT data, that there are three extensional detachments ...
Altherr, Andrew Carter, Avigad, Avigad, Ballard, Barbarand, Black, Boven, Brichau, Brichau, Bröcker, Bröcker, Clauer, Coulson, Dahl, Daniel Stockli, Donelick, Dürr, Esser, Farley, Faure, Forster, Foster, Fytikas, Galbraith, Gessner, Godfriaux, Green, Hejl, Hourigan, House, Hurford, Hurford, John, Kelley, Ketcham, Ketcham, Kumerics, Lee, Lister, Maluski, Maurice Brunel, Mehl, Melidonis, Miller, Patriat, Patrick Monié, Patzak, Pearce, Rahn, Regenauer-Lieb, Reiners, Ring, Ring, Ring, Ring, Ring, Ring, Ring, Ring, Robert Bolhar, Robertson, Samson, Schmädicke, Shaked, Stern, Stockli, Stockli, Stéphanie Brichau, Stöckhert, Tagami, Thomson, Tomaschek, Uwe Ring, Villa, Watson, Weidmann, Wijbrans, York, Zeffren   +79 more
core   +3 more sources

Alpha-recoil in U?Pb geochronology: effective sample size matters

Contributions to Mineralogy and Petrology, 2003
Displacement of the daughter isotope by α-recoil results in an open system on the nanoscale. For a heterogeneous distribution of U and Th, this redistribution of intermediate and stable daughter isotopes results in subvolumes with a deficit of Pb and others with an excess of Pb.
openaire   +3 more sources

P–T Modelling Constrains the Depth of Emplacement of the Porto Azzurro Pluton and Implies Minor Exhumation Caused by the Zuccale Fault (Island of Elba, Italy)

Journal of Metamorphic Geology, EarlyView.
ABSTRACT Understanding the pressure of emplacement of granitic intrusions is crucial to understanding the exhumation history of plutons and constraining the tectonic setting of magma emplacement. However, P–T and geochronological constraints from exhumed plutons are often characterized by large uncertainties, especially in shallow crustal settings with
Samuele Papeschi, Marco Bonini, Matteo Lupi, Chiara Del Ventisette, Domenico Montanari   +4 more
wiley   +1 more source

U-Pb chronology of the Solar System's oldest solids with variable 238 U/ 235 U

, 2016
Accurate determination of the absolute ages of the oldest Solar System objects - chondrules and Ca-Al-rich inclusions (CAIs), requires knowledge of their 238U/235U ratios.
Amelin, Yuri, Iizuka, Tsuyoshi, Ireland, Trevor, Jacobsen, Stein, Kaltenbach, Angela, Petaev, Michail, Stirling, Claudine H   +6 more
core   +1 more source